上海快三推荐三同号推荐 www.ynlxb.com Non-ferrous metals (English name: non-ferrous metal), non-ferrous metals, also known as the narrow non-ferrous metals, all metals are collectively referred to as iron, manganese, chromium outside. Generalized non-ferrous metals also include non-ferrous alloys. A ferrous alloy is an alloy of non-ferrous metal substrate (typically greater than 50%), by adding one or several other elements constituted.
Non-ferrous metals Category:
Light metal:Density less than 4500 kg / m3, such as aluminum, magnesium, potassium, sodium, calcium, strontium, and barium.
Heavy Metal:Density greater than 4500 kg / m3, such as copper, nickel, cobalt, lead, zinc, tin, antimony, bismuth, cadmium, mercury and the like.
Precious Metals:Expensive than the commonly used metal prices, low crustal abundance, purification difficulties, such as gold, silver and platinum group metals.
Semi-metallic:Properties at between metal and nonmetal such as silicon, selenium, tellurium, arsenic, boron, and the like.
Including rare light metals such as lithium, rubidium, cesium, etc.;
Rare refractory metals such as titanium, zirconium, molybdenum, tungsten, etc.;
Dispersing rare metals such as gallium, indium, germanium, and thallium;
Rare earth metals, such as scandium, yttrium, a lanthanide metal;
Radioactive metals such as radium, francium, polonium and actinides uranium and thorium.
Historically, the material used in the production of tools continue to improve, its relationship with the development of human society is very close. Thus historians have used the material objects to mark the historical period, such as the Stone Age, Bronze Age, Iron Age and so on. To the 17th century is a clear human understanding and application of non-ferrous metals were eight kinds. The Chinese nation has had a significant contribution (see History of Metallurgy) in the discovery and production of non-ferrous metals. After the 18th century, the rapid development of science and technology, promoting the discovery of many new non-ferrous metal elements. In addition to the above eight kinds 64 kinds of nonferrous metals outside before the 17th century was known applications were found 13 kinds in the 18th century. 19th century discovered 39 species of the 20th century, they found four species.
The status of non-ferrous metals
Non-ferrous metals is the national economy, people's daily lives and the defense industry, science and technology essential for basic materials and important strategic materials. Modernization of agriculture, industrial modernization, the modernization of national defense and science and technology are inseparable non-ferrous metals. For example, a large component or components required for aircraft, missiles, rockets, satellites, nuclear submarines and other sophisticated weapons and atomic energy, television, communication, radar, computer and other cutting-edge technologies are made of light metal and non-ferrous metal ene made??; addition no nickel, cobalt, tungsten, molybdenum, vanadium, niobium alloy there is no production of non-ferrous metals. Non-ferrous metals in certain applications (such as the power industry, etc.), the usage is quite impressive. Now many countries, especially in industrialized countries, striving to develop non-ferrous metals industry, non-ferrous metals increased strategic reserves.
Non-ferrous metal mining
Non-ferrous metals industry, including geological exploration, mining, milling, smelting and processing sectors. Non-ferrous metal ore content is generally low, in order to obtain one ton non-ferrous metals, often mined as well as tons more than one hundred tons of ore. So mine is an important foundation for the development of non-ferrous metals industry. Non-ferrous metal ores often a variety of symbiotic must therefore be reasonable to extract and recover useful components, good utilization for the rational use of natural resources. Many species of rare metals, precious metals and sulfuric acid and other chemical products, non-ferrous metal ores are in the process or intermediate products as well as slag, dust recovered get. Non-ferrous metal production process usually produces a lot of waste gas, waste water and waste, which contains a variety of useful components, and sometimes contain toxic substances, some of the non-ferrous metals are also toxic. Therefore, in the production of non-ferrous metals in the process, you must pay attention to utilization and environmental protection.